Lock bolt



Patented July 2, 1935 r UNITED STATES PATENT OFFICE 1 V I 2,006,461 t r LOCK BOLT Henry John Kramer, Memphis, Tenn.

Application Jul iv, 1934, Serial No. 735,588

' 3 Claims. (01.151-21) This invention relates to lock bolts and has of the bolt shank. Accordingly, rotational movefparticular reference'to boltsin which a portion ment of the nut in either direction is thereafter ofthenut is distorted into interlockingcooperaimpossible, and the nut is, permanently locked I tion'witha corresponding portionof the shank of in place. Y

5 the b 1t, s For a more complete understanding of the in- 5 Variousforms of interlockingnut and bolt ar- Vention, reference may be had to the accompanyrangements have been devised heretofore, but ing drawing, in which: these earlier arrangements either require the use i Fig. 1 is a side view of the new look bolt of this of an additional part such as acotter pin, lock invention shown in partial'section; H Jo washer or the like, and are therefore objection- Fig. 2 is a cross-section of the nut; I able, or, if the'bolt and nut are adapted to be Fig. 3 is an enlarged crossesection through the locked together by distortion of some portion of lock bolt as seen along the lines 3'3 of Fig. 1; either, the lock does not remain secure under and v j r V My severe operating conditions, and the nut .e'ven- Fig. 4 is a similar View of a modified form of '15 tually works loose. e 100k bolt.

I have found by a series of experiments and Referring to this drawing, numeral 10 desigtests in actual railroad service that it is necessary nates a conventional bolt, the threaded shank of to provide more than a simple interlock between which is provided with the longitudinal slot or thenut and bolt by distortion of one or the other; g o v W c preferably terminates at some an actual extrusion or flowing of the metal of one point between the head l3 of the bolt and the end 20 of the parts such as the nut, over a sharp edge in of the shank threads. I 1 the other part, which prevents rotative movement s illustrated in the oss sectional between them in both directions, is necessary to Shape Of the s or ove 12 is ec angu ar. provide an interlock betweenthem, which is suf- That e pposite walls M thereof are subficiently secure to remain unchanged after long Stantially parallel Because Of the parallel e a- 25 periods of most severe service. Accordingly, I tion of the opposite walls M of the slot or groove have devised a lock bolt in which the nut is the a e A fo med between each of these locked in the bolt against turning movement in Wells 12 nd t e Corresponding surface of the both directions by extruding a portion of it by Shank H is an acute angle, being l than means of a sharp blow over two substantially opso that two sharp-knife like edges I5 are formed 30 positely-directed sharp edges on the bolt after l hw of shank ll. Th ed e I5 al o nth t has been Screwed m pose each other, being located at opposite sides In the preferred embodiment of the new lock O the Slot groove bolt of this invention, thethreaded shank of Considering the f at o of the a p edges 5 t 1 11; i provided ithva, longitudinal Slot or l5, in another way, it will be observed that there groove of such shape'that'two parallel, sharp, flre'less than e the reason that e-Opposite substantially oppositely-directed edges are Wells Ofth'e' Slot groove I? lie outside of the fo med, one between each wall of t 1 1; and t radii R of the shank section which lead'from the corresponding threaded surface of the bolt shank edges 7 40 which form an angle of less than 90 and conse- If desired the Shank H of the bolt It} ay be 40 quently a sharp knife-like edge between each hardened so that the sharp edges E5 will be hardotheh In order to Secure an edge of such sharper than the material from which the nut I6 is ness, the bolt slot or groove is provided with submadestantially parallel Walls or with inwardly diverg- The nut It is illustrated in ion Fig. 2 and ing or undercut walls. The nut is formed with ay be of conventional design except the p 45 a relatively thin, soft metal collar or flange, which Vision Of a 0011a! flange vll which is threaded,

' is threaded t [increase t urfa Contact to increase the contacting surface between the nut tween t t and t shank, and which is it and the shank H of the bolt It]. The collar or adapted to be struck a sharp blow with a, suitflange It is relatively thin and of so t metal so v able blunt tool immediately over the bolt slot as to be reedlly dlstelted- 5 or groove, after t t has been tightened or In utilizing the new look bolt of this invention, screwed home, so that the metal of the nut collar the belt is pp in the usual y, e nut or flange is not only distorted into the bolt slot being w d heme tig tened. After the or groove, but is extruded in both directions over nut l5 has been tightened to'the proper degree, a

the two oppositely-directed sharp knife-like edges blunt tool is placed against the collar or flange I1 55 opposite the slot or groove l2 in the shank l l and struck a sharp blow so as to distort that portion I8 of the collar or flange 11 into the slot or groove 12 in the manner illustrated in Figs. 1 and 3. Due to the sharpness of the knife-like edges 15, the soft metal of the flange or collar I! of the nut I6 is not only forced into the slot or groove [2 but the metal is extruded over both sharp edges I5, the metal flowing to either side thereof. Both edges, I5, because of their sharpness, accordingly bite into the metal of the flange or 001- lar l1 of the nut l6.

It will be observed that the right hand sharp edge l5 eifectively opposes rotational movement of the nut E5 in a clockwise direction, as seen in Fig. 3, while the left hand edge I 5, being opposed to the right hand edge l5, effectively prevents rotational movement of the nut !6 in a counter clockwise direction, as seen in Fig. 3. Thus, with the new look bolt of this invention the nut is not only prevented from turningoif the threaded shank of thebolt 12 because of vibrational or other forces to which it may be subjected, but it is also preventedfrom working loose by turning in the opposite direction, which takes place in some instances, especially where the parts clamped by the bolt wear or compact in some way.

Accordingly, the nut I6 is locked against rotational movement in either direction and cannot work loose even under the most severe operating conditions. For example, the new look bolt has been tested with great success by utilizing it to secure the fish plates of a railroad to theties on a sharp curve where such severe strains are imposed on the nut as would ordinarily result in its working loose in time, either by turning off under the vibration and severe strain or by turning in the reverse direction under repeated pounding with the result that it works back and forth and eventually loosens sufficiently to subsequently allow the nut to turn off. Under these severe conditions the nut of the new bolt did not loosen in any way but remained tight after along period of time.

In the modified form of the invention illustrated in Fig. 4, the elongated slot or groove l 9 in the shank 20 of the bolt is formed with inwardly diverging side walls 2| so that the angle A is even less than the angle A in the form illustrated in Fig. 3, with the result that the sharpness of the knife edge '22 is accentuated. Accordingly the distortion of the flange or collar 23 of the nut 24 into the slot or groove l9 takes place as is indicated at 25, with the result that the extrusion or flowing of the soft metal over the sharp edges 22 is greater in degree and the locking action is more secure.

It will be seen that the new look bolt of this invention provides absolute security under all working conditions and renders a simple form of locking arrangement more useful than it has been heretofore without requiring additional parts or special operations in manufacture and assembly. Although the rectangular and dovetail shaped slots or grooves 12 and I9, respectively, have been illustrated and described, it is to be understood that any other shape of slot which secures the sharp knife-like edge having an angle of less than lies within the scope of this invention.

I claim:-

1. A bolt having a longitudinal slot extending along the threaded surface of the shank thereof, both opposite walls of said slot forming an angle of less than 90 with the corresponding adjacent surface of the shank to provide opposing sharp edges lengthwise of the shank, and a nut on the threaded shank of the bolt having a relatively thin collaradapted to be distorted at one point into the slot and extruded over both opposing sharp edges thereof, whereby one of said walls upon relative rotation of the nut and bolt forces the extruded portion of said collar toward the bottom of the slot. Y

2. A bolt having a longitudinal slot extending along the threaded surface of the shank thereof, the opposite walls of said slot being parallel and forming an angle of, substantially less than 90 with the corresponding adjacent surfaces of the shank to provide opposing sharp edges extending lengthwise of the shank, and a nut on the threaded shank of the bolt having a relatively thin collar adapted to be distorted at one point into the slot and extruded over both opposing sharp edges thereof, whereby one of said walls upon relative rotation of the nut and bolt forces the extruded portion of said collar toward the bottom of the at one point into the slot and extruded over both opposing sharp edges thereof, whereby one of said walls upon relative rotation of the nut and bolt forces the extruded portion of said collar toward the bottom of the slot.

HENRY JOHN KRAMER. 

